Furnaces which comprise a loading chamber in which the melting of light metal loads occurs, are known. These furnaces have a loading chamber connected to a chamber which is placed at a lower level, in which the bath is held in the molten state and in which its tapping occurs. These furnaces are utilized especially for melting light metals and the casting of new parts.
The problem which arises with this type of installation is that it pertains to relatively small units, the operation of which must be as simple and reliable as possible, and which yield must be as high as possible.
The object of the invention is a process and a device for the improved melting of light metal alloy loads. The furnace constructed in accordance with the invention specifically possesses improved compactness and thermal yield in comparison to similar known devices.
The process in accordance with the invention for the melting and holding in the molten state of light metal alloy loads is the type which utilizes a furnace comprising a first loading chamber, which is placed at an upper level, in which the melting occurs, being connected by a channel to a second chamber which is placed at a lower level, in which the bath is kept in the molten state and in which its tapping occurs, with each chamber having a separate burner and with the furnace being endowed with a common evacuation chimney for the combustion fumes produced in each chamber. According to the invention, the process is characterized in that, at an intermediary level, towards the bottom of the first chamber, an exchange of heat is effected between the combustion products and the combustion air utilized for at least one of the burners. In this manner, a particularly compact construction and a notably improved thermal yield are at once obtained, due to the thermal exchange with the combustion products issuing from the two burners before their escape through the chimney.
According to another characteristic of the process according to the invention, a complete loading of the first chamber with the products to be melted is provided, the burner is placed in said loading chamber, approximately at an axial end of said chamber, with the burner being directed towards the other end and with only one passage, connecting with the lower chamber, having a very small section, being provided at a low point in said loading chamber. In this manner, a maximum heating yield is obtained for the load to be melted, and the melting process for the load, which is placed entirely in the flux of heat directed in the axial plane of the chamber, is accelerated.
According to another characteristic of the process according to the invention, the holding burner is placed in said lower holding and tapping chamber, towards the ceiling of said chamber, with said burner being of the flat radiating flame type. In this manner, the holding of the molten state of the bath is achieved under the best conditions, while reducing the agitation of the bath and the formation of oxidation products.
The invention also pertains to a device for the implementation of the aforementioned process, which comprises two adjacent modules, with one placed at a higher level than the other, respectively forming the aforementioned upper loading-melting chamber and the lower holding-tapping chamber, and a heat exchanger for the combustion air/combustion products, which is placed approximately under the base of the upper chamber and beside the internal lateral wall of the lower chamber.